程序实在不能理解，求注解

Question

#include <stdio.h>
#define N 3
#include <stdio.h>
struct student
{int num;
char name[20];
char sex;
int age;
};
struct student stu[N]={{10101,"i Lin",'M',18},{10102,"Zhang Ping",'M',19},{10103,"Wang Min", 'F',20}};
void main()
{
struct student find(int n);
struct student stu n;
intn;
printf("n=");
scanf ("d", &n);
stu n=find(n);
if (stu n.num!=0)
{
printf(" No. Name sex age\n");
printf("5d -20s 2c 4d\n",stu n.num, stu n.name, stu_n.sexp
stu n.age);
}
else
printf ("Not Found!\n");
}
struct student find(int n)
{
struct student stu n;
inti;
for(i=0;i<N;i++)
if (stu[i].num==n)
{
stu_n=stu[i];
break;
}
if(i==N)
stu n.num=0;
return (stu n);
}

Answer 1

一个输入学号，然后在结构体数组中查找是否有该学号的学生的例子